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Abstract:

A method for the creation of subsurface water management systems that
place subsurface drainage lines at a consistent grade and within defined
elevation bounds throughout a field with topographical undulation and
inconsistent slopes, incorporate control weirs for dividing the
subsurface into elevation and acreage zones, place and size surface to
subsurface, size and determine inside surface of drainage mains and
laterals according to the desired coefficient of the subsurface system,
and determine the amount of water required at irrigation inlets in order
to deliver a determined amount of water into the subsurface system for
purposes of irrigation.

Claims:

1. A method for generating a subsurface drainage system that maintains a
set slope and consistent depth for tile laterals throughout a specified
area comprising: gathering GPS data of said specified area, said GPS data
comprising a longitude, latitude and altitude of a plurality of points
along a perimeter of said specified area and an interior of said
specified area; transferring said gathered GPS data to a management
computer; storing said gathered GPS data in said management computer;
generating in said management computer a contour map of said specified
area using said gathered GPS data; and designing by said management
computer a drainage system from said contour map and said GPS data,
wherein said designing comprises: placing with said management computer a
tile main in said design from an outlet to a location of highest
elevation in said specified area, wherein a path taken by said tile main
follows an outside border of the specified area; determining with said
management computer a required slope of the tile main so as to minimize
the number of changes in slope in said tile main while maintaining said
tile main within a bounded depth range from the ground level; inputting
into said management computer with an input device a desired bounded
distance from tile lateral to tile lateral, grade, and bounded depth
range from ground level; placing in said design with said management
computer a first tile lateral connecting to said tile main, wherein said
first tile lateral is placed at a starting location, direction, and
footage so as to maintain inputted entered desired bounded distance from
tile lateral to tile lateral, slope, and bounded depth range from ground
level and wherein a new direction and a footage of the new direction of
said first tile lateral are determined by said management computer until
a final defined footage of said first tile lateral is reached; and
placing in said design with said management computer a second tile
lateral connecting to said tile main, wherein said second tile lateral is
placed at a starting location, direction, and footage, wherein said
second lateral will vary in distance to said first lateral within said
defined bounded distance from tile lateral to tile lateral as undulations
in the topography of the field may be inconsistent between the paths of
said first tile lateral and said second tile lateral

2. A method for generating a subsurface drainage system according to
claim 1, wherein designing said drainage system further comprises:
determining with said management computer locations of a first control
weir and a second control weir.

3. A method for generating a subsurface drainage system according to
claim 2, wherein said locations of said first control weir and said
second control weir are determined by said management computer according
to a specified distance from said first control weir to said second
control weir and a specified number of acres to be controlled by said
first control weir.

4. A method for generating a subsurface drainage system according to
claim 3, wherein said management computer determines said specified
distance from said first control weir to said second control weir based
upon an inputted water table height and an inputted amount of water to be
controlled a within said specified number of acres to be controlled by
said first control weir.

5. A method for generating a subsurface drainage system according to
claim 3, further comprising: placing in said design with said management
computer an irrigation inlet in each control weir.

6. A method for generating a subsurface drainage system according to
claim 1, further comprising: generating with said management computer
machine code for installing a designed drainage system.

7. A method for generating a subsurface drainage system according to
claim 1, wherein designing said drainage system further comprises:
determining with said management computer an acreage draining into a
depression and a volume of water that will enter into the inlet under a
theoretically optimal situation of saturation above an outlet with no
obstructions under multiple sizes and types of surface to subsurface
inlets; inputting into said management computer a desired drainage
coefficient and type of surface to subsurface inlet; and sizing with said
management computer said surface and subsurface inlet and a tile main
according to a volume of water entering through the surface to subsurface
inlet, the specified drainage coefficient, the slope of tile main, and
additional laterals and mains attached to the main for which the surface
to subsurface inlet is draining.

8. A method for generating a subsurface drainage system according to
claim 1, wherein designing said drainage system further comprises:
determining with said management computer required diameter sizes and
inside surface of tile laterals and mains according to a specified
calculation.

9. A method for generating a subsurface drainage system according to
claim 8, wherein said determining required diameter sizes and inside
surface of tile laterals and mains further comprises: automatically
assigning with said management computer sequence numbers to all tile
laterals and mains; selecting a main by its sequence number using an
input device; specifying a drainage coefficient for the selected main;
determining with said management computer said selected main's length,
slope, and number of laterals, mains, and surface to subsurface inlets
connected to said selected main; and calculating with said management
computer a required size of said selected main and inside surface to meet
said specified drainage coefficient with the conditions of length,
perforation, slope, and number of laterals, mains, and attachments to the
main.

10. A method for generating a subsurface drainage system according to
claim 9, wherein said determining required diameter sizes and inside
surface of tile laterals and mains further comprises: calculating with
said management computer a required size and inside surface of laterals
attached to said selected main based on said drainage coefficient entered
in for the main.

11. A method for generating a subsurface drainage system according to
claim 10, further comprising: modifying said design as to incorporate the
changes of tile size and inside surface into information provided for a
bid sheet, map printing, and installation commands for a tile machine.

12. A method for generating a subsurface drainage and irrigation system
design that maintains a set slope and consistent depth for tile laterals
throughout a specified area comprising: placing with a management
computer and a contour map of said specified area a tile main in said
design, wherein said tile main extends from an outlet to a location of
highest elevation in said specified area, wherein a path taken by said
tile main follows an outside border of the specified area; determining
with said management computer a required slope of the tile main so as to
minimize the number of changes in slope in said tile main while
maintaining said tile main within a bounded depth range from the ground
level; inputting into said management computer with an input device a
desired bounded distance from tile lateral to tile lateral, grade, and
bounded depth range from ground level; placing in said design with said
management computer a first tile lateral connecting to said tile main,
wherein said first tile lateral is placed at a starting location,
direction, and footage so as to maintain inputted entered desired bounded
distance from tile lateral to tile lateral, slope, and bounded depth
range from ground level and wherein a new direction and a footage of the
new direction of said first tile lateral are determined by said
management computer until a final defined footage of said first tile
lateral is reached; placing in said design with said management computer
a second tile lateral connecting to said tile main, wherein said second
tile lateral is placed at a starting location, direction, and footage,
wherein said second lateral will vary in distance to said first lateral
within said defined bounded distance from tile lateral to tile lateral as
undulations in the topography of the field may be inconsistent between
the paths of said first tile lateral and said second tile lateral;
determining with said management computer locations of a first control
weir and a second control weir, wherein said locations of said first
control weir and said second control weir are determined by said
management computer according to a specified distance from said first
control weir to said second control weir and a specified number of acres
to be controlled by said first control weir and said management computer
determines said specified distance from said first control weir to said
second control weir based upon an inputted water table height and an
inputted amount of water to be controlled a within said specified number
of acres to be controlled by said first control weir; placing in said
design with said management computer an irrigation inlet in each control
weir; determining with said management computer acreage sizes of each of
a plurality of irrigation zones in said specific area; inputting with an
input device a rate and amount of water to be added to the system;
calculating with said management computer a volume of water to be
supplied to each irrigation zone so as to apply water uniformly to the
system at the rate and total amount desired; and determining with said
management computer a size of an irrigation pressure line for each
irrigation inlet and the total gallons per minute required by an
irrigation pump.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of the filing date of
U.S. Provisional Patent Application Ser. No. 61/647,237 filed by the
present inventors on May 15, 2012.

[0002] The aforementioned provisional patent application is hereby
incorporated by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0003] None.

BACKGROUND OF THE INVENTION

[0004] 1. Field of the Invention

[0005] The present invention relates broadly to the field of agriculture,
and more specifically to the use of topographic data in the field of
agriculture

[0006] 2. Brief Description of the Related Art

[0007] In the field of agriculture, irrigation systems water crop fields,
and tile systems manage water drainage in crop fields. Often, irrigation
and tile systems are "sub surface," or installed underground. Networks of
pipe and/or tubing are installed underground for both systems, including
main collector lines and a number of outlets. Outlets drain excess water
into non-crop areas or drainage ditches which move the water away from
crop fields. One or more junction boxes may be installed to check flows,
sub mains, and drains. Irrigation and tiling systems are placed to
provide the surrounding topography the best possible water supply and
drainage. Additionally, outlets are placed where they are best protected
from erosion, settlement, rodents, silting, shifting and damage by
machinery and livestock. Discharge outlets further must be placed above
the natural water level or bottom of a drainage ditch so that discharged
water can drain freely.

[0008] Generally, this requires drainage to be staged at various grades,
effectively using gravity to effect draining. However, where needed,
pumps can be installed to facilitate drainage.

[0009] In order to properly position and install sub surface systems,
contractors must assess the topography of the land. To do so, a
topographical map of the area is prepared. A topographical map represents
a three-dimensional land surface on a two-dimensional plane, for example,
a map on a piece of paper. A topographical map uses lines and symbols to
represent features in relation to the earth's surface. Terrain shape and
elevation are depicted with contour lines.

[0010] To prepare a topographical map, a survey must be taken to determine
horizontal and vertical measurements of various elevation points. These
horizontal and vertical measurements can be gathered either by using a
Global Positioning Systems (GPS) or surveying from a known benchmark.
Specific elevation points are triangulated, and topographical maps are
developed by hand from the triangulated data set.

[0011] Using the topographical map, an engineer and/or contractor,
typically, uses the information to design a tile system. The
topographical map further provides elevational information that is
especially important to programming machine tools used to install the
tile system.

[0012] Other current systems collect data points using survey grade,
Real-Time Kinematic (RTK) Differential Global Positioning Systems (DGPS).
In order to generate a topographical map from the RTK system data, the
collected data must first be transferred to a CAD program. The latitude,
longitude, and altitude coordinates must be converted into a datum set
for compatibility with CAD. The profile is then developed in CAD.
Automated installation machines are grade controlled using the
topographic map, and use the latitude, longitude, and altitude data
generated by the RTK system. To use the topography data generated by CAD,
the x,y,z datum sets must be converted back to latitude, longitude, and
altitude data points. This repeated conversion degrades the precision of
the data point locations.

[0013] U.S. Pat. Nos. 8,155,935 and 7,315,800 disclosed a system and
method of managing the design and installation of agricultural water
management systems. Another aspect was the provision a comprehensive
system and method of managing the design and installation of water
management systems, which reduces the amount of interface equipment, and
reduces cost. The system and method provided comprehensive design and
installation management for water management systems. Maps and grade
profiles were created from data collected by Global Positioning devices
in the field. Latitude, longitude, and elevation were triangulated from
GPS data to develop contour, grade, and profile maps, used to design
irrigation and drainage systems in real time. Customer billing
information and vendor pricing information were then produced from map
and grade profile data. Interfacing and machine control for machines used
to install irrigation and/or drainage systems were generated from
contour, grade and profile data. Data was exported and imported in common
file formats for efficient data exchange.

SUMMARY OF THE INVENTION

[0014] The system and method of the present invention provide a
comprehensive method for the creation of subsurface water management
systems that place subsurface drainage lines at a consistent grade and
within defined elevation bounds throughout a field with topographical
undulation and inconsistent slopes, incorporate control weirs for
dividing the subsurface into elevation and acreage zones, place surface
to subsurface inlets (e.g., French Drains, post risers, etc.) designed
according to the desired drainage coefficient of the subsurface system,
size and determine type of drainage mains and laterals according to the
desired coefficient of the subsurface system, and determine the amount of
water required at irrigation inlets in order to deliver a determined
amount of water into the subsurface system for purposes of irrigation.
The above improvements are all part of the design process of creating a
subsurface drainage system. As such, all of the mentioned additions are
to build upon the integrated process described in U.S. Pat. Nos.
8,155,935 and 7,315,800, both of which are incorporated herein in their
entirety.

[0015] Prior to this invention, subsurface drainage laterals have been
designed for fields with undulating topography in a fashion where drains
vary in grade and depth according to the undulations of the topography of
the field. This invention allows for a method of designing the placement
of subsurface drainage laterals so as to have a set grade and consistent
depth for all laterals within the field regardless of undulations in
topography. Such a method is best referred to as contour drainage design,
as the placement of the subsurface drainage laterals matches closely to
the natural contours of a field. The advantages of such placement of
subsurface drainage laterals are a consistent water table is maintained
throughout the field and subsurface drainage laterals intercept
subsurface water flows without the need of dirt moving or land leveling
in order to alter the natural topography of the field. Such placement of
subsurface drainage laterals on the contour is a marked improvement over
traditional methods of placing subsurface drainage laterals known as
pattern or system tile.

[0016] Prior to this invention, control weirs were placed according to
hand calculation without reference to lateral depth or acres to be
controlled. This invention allows for placement of control weirs based on
the depth of subsurface tile laterals relative to the location of the
control weir on a subsurface main or sub main so that elevation zones as
measured from the ends of tile laterals can be calculated almost
instantaneously. Similarly, control weirs can also be placed based on the
acreages covered by tile laterals, sub mains, and mains so as to
eliminate the difficulties from too large of an amount of water to be
controlled by a particular control weir. The advantage of this method of
placement allows for control weirs to divide a field into set elevation
zones for the control of the field's water table and also to eliminate
undesired movement of water from one zone to another. Gate placement in
such a fashion is a marked improvement on a method of water management in
agriculture known as controlled drainage.

[0017] Prior to this invention, surface to subsurface inlets used to
quickly move surface water from field depressions to a subsurface tile
system were designed in terms of size and location by hand calculation
without an automated means of determining the location or size of surface
to subsurface inlets or the size of mains required to manage the desired
amount of water to be removed by the surface to subsurface inlet. The
present invention allows for the automated placement of surface to
subsurface inlets and a determination of the size required of the surface
to subsurface inlet to drain the amount desired to be removed from the
surface. In addition, this invention allows for the determination of the
required size of the subsurface tile main with respect to the amount of
water removed from the surface to subsurface inlet.

[0018] Prior to this invention, the size of subsurface tile laterals and
tile mains were determined by hand calculation; no automated system
existed to determine size by length, grade, and amount of connections to
other tile laterals and mains. This invention allows for the sizing and
determination of inside surface of subsurface tile laterals and tile
mains based on the length of each line, the slope of the tile, and number
of laterals, mains, and surface to subsurface inlets connecting into the
lateral or main. The size is determined according to the desired drainage
coefficient for the system.

[0019] Prior to this invention, irrigation inlets to a subsurface drainage
system were determined by hand calculation; no automated system existed
to determine location of inlets or the amount of water required to enter
into the system through the inlet in order to provide the desired amount
of water for the system. This invention allows for placement of
irrigation inlets and regulates the amount of water required to enter
through the inlet so as to be able to provide uniform filling of the
subsurface system at the amount desired for irrigation. Size of pressure
line required to move irrigation water and the pump for irrigating can
then be calculated. In addition, this invention allows for the
development of an irrigation schedule under varied climatic scenarios
based on the determined rate of application.

[0020] In a preferred embodiment, the present invention is a method for
generating a subsurface drainage system that maintains a set slope and
consistent depth for tile laterals throughout a specified area. The
method comprises the steps of gathering GPS data of the specified area,
the GPS data comprising a longitude, latitude and altitude of a plurality
of points along a perimeter of the specified area and an interior of the
specified area; transferring the gathered GPS data to a management
computer; storing the gathered GPS data in the management computer;
generating in the management computer a contour map of the specified area
using the gathered GPS data; and designing by the management computer a
drainage system from the contour map and the GPS data, wherein the
designing comprises placing with the management computer a tile main in
the design from an outlet to a location of highest elevation in the
specified area, wherein a path taken by the tile main follows an outside
border of the specified area; determining with the management computer a
required slope of the tile main so as to minimize the number of changes
in slope in the tile main while maintaining the tile main within a
bounded depth range from the ground level; inputting into the management
computer with an input device a desired bounded distance from tile
lateral to tile lateral, grade, and bounded depth range from ground
level; placing in the design with the management computer a first tile
lateral connecting to the tile main, wherein the first tile lateral is
placed at a starting location, direction, and footage so as to maintain
inputted entered desired bounded distance from tile lateral to tile
lateral, slope, and bounded depth range from ground level and wherein a
new direction and a footage of the new direction of the first tile
lateral are determined by the management computer until a final defined
footage of the first tile lateral is reached; and placing in the design
with the management computer a second tile lateral connecting to the tile
main, wherein the second tile lateral is placed at a starting location,
direction, and footage, wherein the second lateral will vary in distance
to the first lateral within the defined bounded distance from tile
lateral to tile lateral as undulations in the topography of the field may
be inconsistent between the paths of the first tile lateral and the
second tile lateral.

[0021] The method may further comprise determining with the management
computer locations of a first control weir and a second control weir. The
locations of the first control weir and the second control weir may be
determined by the management computer according to a specified distance
from the first control weir to the second control weir and a specified
number of acres to be controlled by the first control weir. The
management computer may determine the specified distance from the first
control weir to the second control weir based upon an inputted water
table height and an inputted amount of water to be controlled a within
the specified number of acres to be controlled by the first control weir.
The method may further comprise generating with the management computer
machine code for installing a designed drainage system.

[0022] The designing of the drainage system may further comprise
determining with the management computer an acreage draining into a
depression and a volume of water that will enter into the inlet under a
theoretically optimal situation of saturation above an outlet with no
obstructions under multiple sizes and types of surface to subsurface
inlets; inputting into the management computer a desired drainage
coefficient and type of surface to subsurface inlet; and sizing with the
management computer the surface and subsurface inlet and a tile main
according to a volume of water entering through the surface to subsurface
inlet, the specified drainage coefficient, the slope of tile main, and
additional laterals and mains attached to the main for which the surface
to subsurface inlet is draining.

[0023] Further, the step of designing the drainage system may further
comprise determining with the management computer required diameter sizes
and inside surface of tile laterals and mains according to a specified
calculation. The step of determining required diameter sizes and inside
surface of tile laterals and mains may further comprise automatically
assigning with the management computer sequence numbers to all tile
laterals and mains; selecting a main by its sequence number using an
input device; specifying a drainage coefficient for the selected main;
determining with the management computer the selected main's length,
slope, and number of laterals, mains, and surface to subsurface inlets
connected to the selected main; and calculating with the management
computer a required size of the selected main and inside surface to meet
the specified drainage coefficient with the conditions of length,
perforation, slope, and number of laterals, mains, and attachments to the
main. The step of determining required diameter sizes and inside surface
of tile laterals and mains may further comprise calculating with the
management computer a required size and inside surface of laterals
attached to the selected main based on the drainage coefficient entered
in for the main.

[0024] Still other aspects, features, and advantages of the present
invention are readily apparent from the following detailed description,
simply by illustrating a preferable embodiments and implementations. The
present invention is also capable of other and different embodiments and
its several details can be modified in various obvious respects, all
without departing from the spirit and scope of the present invention.
Accordingly, the drawings and descriptions are to be regarded as
illustrative in nature, and not as restrictive. Additional objects and
advantages of the invention will be set forth in part in the description
which follows and in part will be obvious from the description, or may be
learned by practice of the invention.

[0025] In another embodiment, the present invention is a method for
generating a subsurface drainage and irrigation system design that
maintains a set slope and consistent depth for tile laterals throughout a
specified area. In the method, a management computer and a contour map of
said specified area are used to place a tile main in said design, wherein
said tile main extends from an outlet to a location of highest elevation
in said specified area, wherein a path taken by said tile main follows an
outside border of the specified area. The management computer determines
a required slope of the tile main so as to minimize the number of changes
in slope in said tile main while maintaining said tile main within a
bounded depth range from the ground level. A desired bounded distance
from tile lateral to tile lateral, grade, and bounded depth range from
ground level is inputted into the management computer using an input
device. The management computer places a first tile lateral connecting to
said tile main, wherein said first tile lateral is placed at a starting
location, direction, and footage so as to maintain inputted entered
desired bounded distance from tile lateral to tile lateral, slope, and
bounded depth range from ground level and wherein a new direction and a
footage of the new direction of said first tile lateral are determined by
said management computer until a final defined footage of said first tile
lateral is reached. The management computer places in the design a second
tile lateral connecting to said tile main, wherein said second tile
lateral is placed at a starting location, direction, and footage, wherein
said second lateral will vary in distance to said first lateral within
said defined bounded distance from tile lateral to tile lateral as
undulations in the topography of the field may be inconsistent between
the paths of said first tile lateral and said second tile lateral. The
management computer determines locations of a first control weir and a
second control weir and places them in the design, wherein said locations
of said first control weir and said second control weir are determined by
said management computer according to a specified distance from said
first control weir to said second control weir and a specified number of
acres to be controlled by said first control weir and said management
computer determines said specified distance from said first control weir
to said second control weir based upon an inputted water table height and
an inputted amount of water to be controlled a within said specified
number of acres to be controlled by said first control weir. The
management computer places an irrigation inlet in each control weir in
the design. The management computer determines acreage sizes of each of a
plurality of irrigation zones in said specific area. A rate and amount of
water to be added to the system are input into the management computer,
and the management computer calculates a volume of water to be supplied
to each irrigation zone so as to apply water uniformly to the system at
the rate and total amount desired. Using that information, the management
computer uses a size of an irrigation pressure line for each irrigation
inlet and the total gallons per minute required by an irrigation pump.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] For a more complete understanding of the present invention and the
advantages thereof, reference is now made to the following description
and the accompanying drawings, in which:

[0027]FIG. 1 is a flow diagram of a system and method for design from
survey to installation in accordance with a preferred embodiment of the
present invention. Multiple paths exist within the design process for the
placement of surface to subsurface drains, sizing laterals, sizing mains,
placing control weirs, and setting irrigation inlets.

[0028] FIG. 2 is schematic of an exemplary subsurface tile system. This
schematic shows a tile main, the path to an outlet, and tile laterals.

[0029] FIG. 3 is a schematic of an exemplary subsurface tile system
incorporating control weirs. Note, the tile mains, path to an outlet, and
tile laterals are represented in the same fashion as FIG. 2.

[0030] FIG. 4 is a schematic showing an example of a post riser and a main
increased in size as a result of inclusion of the post riser. Note, the
tile mains, path to an outlet, and tile laterals are represented in the
same fashion as FIG. 2.

[0031] FIG. 5 is a schematic showing an exemplary tile lateral increased
in size due to its length. Note, the tile mains, path to an outlet, and
tile laterals are represented in the same fashion as FIG. 2.

[0032] FIG. 6 is a schematic of an exemplary subirrigation system
including irrigation inlets, set irrigation spickets for uniform
application, pressure line for irrigation water transfer, and the route
to the irrigation pump. Note, the tile mains, path to an outlet, tile
laterals, and control weirs are represented in the same fashion as FIG.
3.

[0033] FIG. 7 illustrates a top down view of a simplified pattern or
system tile subsurface drainage system design overlaid on a simplified
topographical map.

[0034] FIG. 8 is a top down view of a simplified contour subsurface
drainage system design overlaid on a simplified topographical map.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Preferred embodiments of the present invention will be described
with reference to FIGS. 1-8. A subsurface system may be comprised of a
variety of different components. As shown in FIG. 2, a simple system may
have a tile main 210 and a plurality of tile laterals 220. A more
complicated subsurface system, as shown in FIG. 3, may include a tile
main 310, a plurality of tile laterals 320 and a plurality of control
weirs 330 each having a control gate 332 within it. In another variation
as shown in FIG. 4, a subsurface system may have a tile main 410, a
plurality of tile laterals 420, and one or more post risers 430. The tile
main 410 may have an enlarged section or portion 412 to accommodate the
riser 430. Further, as shown in FIG. 5, a tile main 510 may have a
plurality of tile laterals 520, one or more of which may be increased in
size 522 due to their length. A yet more complicated subsurface system is
shown in FIG. 6. A tile main 610 has a plurality of tile laterals 620
connected to and extending from it. The tile laterals 620 may be the same
or different sizes depending on their lengths. The subsurface system may
further include control weirs 630 having control gates 632 within them,
pressure lines 650 connected to an irrigation pump to transfer irrigation
water, irrigation inlets 640 and irrigation spicket sets 634.

[0036] As shown in FIG. 1, multiple paths exist within the design process
for the placement of surface to subsurface drains, sizing laterals,
sizing mains, placing control weirs, and setting irrigation inlets. A
survey of an area to be irrigated is taken 110 such as with a global
positioning system ("GPS"). The GPS is connected, for example, to a
computer or processor, and the survey data from the GPS is transmitted to
the computer or processor and is stored in memory or other storage. The
survey data is then used to create a topography map of the area 120. A
subsurface design is then generated by the processor or computer 130. At
this point, the system and method may place surface to subsurface inlets
140 in the design and then size the laterals 150 or may proceed to
directly sizing the laterals, depending on the particular system being
designed. The placement of the surface to subsurface inlets and sizing of
the laterals is performed via software stored in memory and running on
the computer or processor. Next, the mains in the design are sized 160,
again by software stored in memory and running on the processor or
computer. Depending on the system being designed, control weirs may be
placed in the design 170 and irrigation inlets may be set in the design
180. The system is then installed using the design 190.

[0037] An exemplary simplified pattern or system tile subsurface drainage
system design overlaid on a simplified topographical map is shown in FIG.
7. The topography map shows a small hill in the center of the map with
the darkest section representing the highest elevation, the medium
darkened section the next highest level, and the lightest section the
lowest portion of the field. A subsurface tile main is represented on the
right hand of the map as a dark line running from the bottom of the map
to the top. Subsurface tile laterals are represented as thin straight
lines running to the left from the subsurface tile main. As subsurface
tile laterals must always slope downwards to the subsurface tile main,
the subsurface tile laterals shown as passing through the hill must
necessarily have a greater depth when located below the hill than on
either side, right or left, of the hill.

[0038] A simplified contour subsurface drainage system design overlaid on
a simplified topographical map is shown in FIG. 8. The topography map
shows a small hill in the center of the map with the darkest section
representing the highest elevation, the medium darkened section the next
highest level, and the lightest section the lowest portion of the field.
This hill is identical to the representative hill shown in FIG. 7. A
subsurface tile main is represented in the center of the map as a dark
line running from the bottom of the map to the top of the hill.
Subsurface tile laterals are represented as thin curved lines running
from the subsurface main around the hill so as to represent a subsurface
tile drainage design matching the topography of the hill. As the
subsurface tile laterals are placed in such a manner as they are located
on areas of equal elevation, the subsurface tile laterals may have a set
grade and consistent depth throughout their extent.

[0039] In a preferred embodiment, the present invention is a system and
method having at least five improvements to the prior systems and
methods. The improvements are:

[0040] Method of design of subsurface
drainage laterals that places subsurface drainage laterals with a set
grade and consistent depth throughout a field with an undulating
topography and inconsistent ground level slopes

[0041] Placement of
control weirs according to elevation zones and acreage zones

[0042]
Placement of surface to subsurface inlets and sizing of the main so to
accommodate the surface water in addition to subsurface water

[0043]
Sizing and determination of inside surface of subsurface laterals and
mains according to the amount of water that will be draining into them
based on their length, a specified drainage coefficient, grade, and
number of laterals, mains, and surface to subsurface inlets attached to
them

[0044] Determination of amount of water required at each irrigation
inlet so as to have a uniform application of water to the subsurface dual
purpose drainage and irrigation system

Description and Method of Point 1 (Method of Design of a Contour Drainage
System):

[0045] Subsurface drainage tile systems are a series of slotted pipes,
referred to as tiles in the industry, installed below the surface so as
to lower the water table to the elevation level of the installed pipes.
Subsurface drainage tile systems must be designed so as to have a method
of emptying the pipes of collected waters. The location where tiles are
emptied is known as an outlet. An outlet is often a ditch, creek, pond,
larger pipe, or surface that is lower in elevation from the subsurface
drainage tile system. Gravity is used within a subsurface drainage tile
system to move water from the pipes to the outlet. A slope must be
maintained throughout the subsurface drainage tile system such that water
will flow to the outlet.

[0046] A subsurface drainage tile design is the layout of the tiles used
for a subsurface drainage tile system with the origin of the system being
the outlet. From the outlet, every tile can be described within the
design by its starting location, direction installed, footage installed
at the defined direction, and slope. As tiles need not be installed in
straight lines and may vary in slope along its path, changes in direction
and slope as denoted by footage distance from the starting location may
be included as part of the subsurface drainage tile design. Tiles may
also connect to one another at tees, wyes, or various other forms of
connections. Within the industry of subsurface drainage tile design, the
connection of one or more tiles is typically viewed as the beginning of a
new tile and the end or continuation of the previous tile. At such
connections then, at least one tile is defined with a starting location
located at the connection, a direction installed, footage installed at
the defined direction, and slope. A field or area is considered to have a
completed subsurface drainage tile design if every tile to be located
within the field is defined as above.

[0047] Within the subsurface drainage tile designs a tile that has
multiple connections on it is often referred to as a main. Typically, a
main is a larger size than the tiles that connect to it as it often will
contain more water in it at any given point than tiles without tiles
connected to it. As with other tiles, mains may or may not be connected
to other mains. Tiles are connected to a main and have no connections or
one connection to them are often referred to in the industry as laterals.
Laterals tend to be smaller in size than mains as they will often contain
less water in them at any given point due to the lack of connections to
other tile.

[0048] Methods used for creating the topographical map and subsurface tile
designs are described by U.S. Pat. Nos. 8,155,935 and 7,315,800. The
predominant method of subsurface drainage tile design using the methods
described by U.S. Pat. Nos. 8,155,935 and 7,315,800 and the methods used
prior to the development of U.S. Pat. Nos. 8,155,935 and 7,315,800 are
known as pattern or system tile. These designs have a single main or a
combination of mains from the outlet to a defined location or locations
within the field to be drained. Typically, the main is placed from the
outlet to the highest area of the field along a route that requires the
least amount of depth as measured from ground level to the bottom of the
tile. In some instances, however, the main is installed along a different
route so as to avoid a hazard, preexisting buried objects, or areas of
high erosion. The slope of the main is then determined so as to minimize
the number of times slope must be changed or so as to as closely as
possible maintain an elevation given the topography of the path of the
main. A main may require anywhere from zero to over ten thousand changes
in slope. Often, the main will vary in depth from 2 feet below the
surface to 8 feet below the surface.

[0049] From these mains, laterals are then connected to the main at a
specified distance from one another (e.g., a lateral every 40 feet) and
with a set angle of connection into the main (e.g., perpendicular to the
main, 45 degree angle entering the main from the north, etc.). The
direction of the lateral is then determined so as to maintain the
specified distance determined at the connection. Laterals are installed
in straight lines so as to maintain the specified distance from
connections and reduce installation time. However, in some instances
laterals vary from straight lines so as to avoid hazards, preexisting
buried objects, and areas of high erosion. Sometimes a single lateral may
also be placed parallel to natural land features, such as a grassed
waterway, or the edge of the field. In some cases, these laterals are not
straight lines but rather match the directional changes of the land
feature. The slope of the lateral is then determined so as to minimize
the number of times slope must be changed or so as to as closely as
possible maintain an elevation given the topography of the path of the
main. A lateral may require anywhere from zero to over ten thousand
changes in slope. Often, laterals will vary in depth from 2 feet below
the surface to 6 feet below the surface.

[0050] The described method of pattern or system tile design is common
throughout the industry. The method has been used for over a century and
has been very successful in fields with no undulations in topography and
consistent ground level slopes. A field is considered to have an
undulating topography if it contains at least one location where
traveling in opposite directions results in increasing in elevation
(e.g., a trough) or at least one location where traveling in opposite
directions results in decreasing in elevation (e.g., an apex). A field is
considered to have an inconsistent ground level slope if a line exists
between any two locations in the field such that the absolute difference
in the elevations of one location and the midpoint subtracted by the
absolute difference of the second location and the midpoint is nonzero.
Within fields with no undulations in topography and consistent ground
level slopes, laterals can be designed using the methods described above
with a consistent depth throughout the field and with a consistent slope
equal to the ground slope of the field. Such systems provide a consistent
water table in the field, which is ideal for root development of plants.
However, very few fields occur naturally with no undulations in
topography and consistent level slopes. As a result, earth moving and
land leveling have been used to remove natural undulations and
artificially create a consistent level slope. Preparing fields in such a
fashion have been rare, however, due to the high cost of earth moving and
land leveling.

[0051] Instead, pattern or system tile design has been most often applied
to fields poorly suited for such designs due to undulating topography and
a lack of consistent slope. Several problems are created by pattern or
system tile design used for fields with topographical undulations and
inconsistent ground level slopes. First, tile laterals are designed based
on maintaining a set pattern, set distance from one another, and a set
single direction. Topographical changes are then used to calculate slope
and depth once the pattern is selected. As a result, grade and depth
varies along each and between laterals depending on the undulations of
the topography. This creates a non-uniform water table for the areas
drained by the subsurface drainage system, reducing the effectiveness of
the subsurface drainage system. Second, so as to maintain the defined
pattern of the system, many tile laterals are designed so as to move
parallel to the flow of subsurface water instead of perpendicular to the
flow of subsurface water. Placing laterals in such a fashion reduces the
ability of the subsurface drainage system to intercept subsurface water
flows, reducing the efficiency of the subsurface drainage system. Third,
inconsistent ground level slopes necessitate for some tile laterals
changes in slope so as to avoid tile laterals being installed at a depth
from ground level too deep for the methods used for installation. Changes
in slope, particularly reductions, lower the rate of flow within a tile
and reduce the amount of water that can be moved within the system.
Changes in slope also create greater risk of error during installation
(e.g., creating a reverse grade, known as a bauble, through a space of
air generated between the tip of a tile plow and the boot where tile is
placed from the surface into the cavity created by the plow).

[0052] The present invention provides a method for creating a variant of a
pattern or system tile subsurface drainage system that maintains a set
slope and consistent depth for tile laterals throughout the area covered
by placing laterals at a desired bounded distance from tile lateral to
tile lateral and along paths of natural topographical undulation and
ground level slope. To create such designs, topographical data is
generated, for example, but known methods, and transferred into a
management computer as described according to U.S. Pat. Nos. 8,155,935
and 7,315,800. A contour map is then generated according to the methods
used by U.S. Pat. Nos. 8,155,935 and 7,315,800. A design program is then
initiated that places one or more mains from the outlet to the location
of highest elevation. In placing the main, the path taken is one that
follows the outside border of the area to be covered as far is possible
considering the topography of the field and obstructions within the field
such as hazards, preexisting buried objects, and areas of high soil
erosion. The program then determines the required slope of the main so as
to minimize the number of changes in slope while maintaining within a
bounded depth range from the ground level. Upon completion of the design
of the main, the program may place additional mains connecting to the
outlet or already designed mains that reach areas of the field where the
ground level slopes upwards in all directions, known as a wethole or
pothole in the industry. The program may then further place additional
mains connecting to the outlet or already designed mains that reach areas
of the field where the ground level slopes downwards in all directions,
known as a knob or hill in the industry. The program then determines the
required slope of these mains so as to minimize the number of changes in
slope while maintaining within a bounded depth range from the ground
level.

[0053] Upon completion of the main design, a desired bounded distance from
tile lateral to tile lateral, grade, and bounded depth range from ground
level is entered into the program using an input device such as a
keyboard, mouse or other means for entering data. The program will then
initiate a routine that places a tile lateral connecting to a main. The
lateral will be placed at a starting location, direction, and footage so
as to maintain the entered desired bounded distance from tile lateral to
tile lateral, slope, and bounded depth range from ground level. So as to
maintain these requirements, the program will vary the direction and
footage of the new direction until a final defined footage is reached. In
so doing, a lateral is generated that may change directions from one to
over ten thousand times in order to maintain its set grade and bounded
depth range from ground level. Upon completion of the lateral, a second
lateral is then created by the program located at a distance from the
first lateral within the defined bounded distance from tile lateral to
tile lateral. The lateral is created in a similar fashion to the first
lateral except the second lateral will vary in distance to the first
lateral within the defined bounded distance from tile lateral to tile
lateral as undulations in the topography of the field may be inconsistent
between the paths of the first and second lateral. The process of placing
laterals is then continued until the whole field is covered.

[0054] Those familiar with the industry will recognize the novelty of such
a method as in all previous methods of design direction and footage are
defined and then slope and bounded depth range from ground level
calculated. By defining slope and the bounded depth range from ground
level and then calculating the necessary direction and footage of the
direction a lateral is generated that maintains a set slope throughout a
lateral and between laterals and that all laterals will be within the
bounded depth range from the surface of the field. This method is known
as contour drainage as the tiles appear to follow the contour lines of a
topographical map of a field.

[0055] The benefits of the described method of contour design are
numerous. First, the consistent bounded depth from elevation maintained
by the design allows for a consistent water table to be maintained
throughout the area covered by the design. Second, as laterals designed
in this manner run perpendicular to the slope of ground level, each
lateral functions as an interceptor to subsurface water movement. Third,
as changes in slope do not occur for laterals, chances of error due to
changing slope are eliminated for laterals.

[0056] Upon completion of design, a routine within the program can be
initiated with an input device such as a mouse or keyboard that generates
a machine code for installation as described by U.S. Pat. Nos. 8,155,935
and 7,315,800.

Description and Method of Point 2 (Placing Control Weirs):

[0057] Control weirs are vertical pipes or gates installed in a box on a
main and have been used in subsurface drainage systems for over half a
century. They are vertical barriers to the water flow within a main so
that water must rise to the height of the vertical pipe or gate before it
can continue to flow down the main. This occurs when the water table of
the field above the control weir rises so as to equal or exceed the
height of the vertical pipe or gate. The reason these are installed is
simply to raise the water table of a field above the level of the
subsurface tile drainage system. This slows down the movement of water
off of the field, provides more water for the crops within the field, and
reduces the amount of water soluble pollutants entering waterways. In the
past, control weirs have typically been installed only at the end of
subsurface drainage systems or randomly throughout a system.

[0058] Under the present invention, gates are placed on completion of a
design of a subsurface drainage system as described in point 1 but prior
to generation of a machine code for installation as described by U.S.
Pat. Nos. 8,155,935 and 7,315,800. After having a complete design, a
routine is initiated within the management computer software through an
input device such as a mouse or keyboard that determines for each main
the location of control weirs according to specifications entered into
the routine. The two specifications used are vertical distance from the
first control weir to the next control weir as measured from the end of
tile laterals and number of acres served by a control weir. In doing so,
the software will place control weirs at the exact latitude, longitude,
and elevation along the main so as to maintain the specifications on
height and acreage. The specifications are determined by the desired
height of a water table and estimated amount of water to be controlled
within the acreage served by a zone. The benefit of doing this is that by
placing gates according to these specifications the water table can be
more successfully raised and head pressure within the main reduced so as
to reduce the likelihood of water flowing around the control weir through
the soil profile so as to make the control weir ineffective. This is a
far superior method of controlled drainage than the methods used prior to
this invention. The information on control weirs can then be taken to the
field so that the information on latitude, longitude, and elevation of
the vertical pipe or gate is apparent to the contractor for installation.

[0059] Upon completion of control weir placement, a routine within the
program can be initiated with an input device such as a mouse or keyboard
that generates a machine code for installation as described by U.S. Pat.
Nos. 8,155,935 and 7,315,800.

Description and Method of Point 3 (Surface to Subsurface Inlets):

[0060] Surface to subsurface inlets are openings from the surface to a
subsurface drainage system that allow accumulated surface water to move
with little restriction from the surface to the subsurface tile system.
There are two main forms of such inlets in agriculture, a post riser and
a French Drain. A post riser is a vertical pipe that goes from the
surface directly into a tile main or lateral; it typically will have a
brightly colored cover on it with large holes in it so as to be noticed
by the farmer while working a field and also to block large objects from
entering the tile system. Post risers function in the exact same manner
as sewer drains in the city. French Drains are shallow large slotted
subsurface drains with the soil above the drain removed and replaced with
gravel. These operate much like post risers but do not require a
hindrance in the field. Surface to subsurface inlets are most commonly
placed in natural and manmade depressions in a field, known as wetholes
or potholes. These types of inlets have existed for as long as subsurface
tile drains have existed and have nearly always been placed through
observing water pooling.

[0061] The water brought into the surface to subsurface inlet must then
flow into a tile main and eventually into an outlet. The size of the
surface to subsurface inlet and the size of the tile main determine how
rapidly the water can be removed from the depression. The size of the
surface to subsurface inlet is determined by the acreage of the
depression. The process of determining the size of the tile main has been
done exclusively by hand calculation based on the amount of water
determined to be draining into the surface to subsurface inlet.

[0062] In the present invention, the location of the surface to subsurface
inlet and size of the main attached to the surface to subsurface inlet is
determined in the design process as described in point 1 above and can
incorporate additional information into the sizing function of the main
as described in point 3 below. With a completed design as described in
point 1, a routine is initiated in the software using an input device
such as a keyboard or mouse that identifies potential locations of
surface to subsurface inlets. The routine then determines the acreage
draining into the depression and determines volume of water that will
enter into the inlet under a theoretically optimal situation of
saturation above the outlet with no obstructions under multiple sizes and
types of surface to subsurface inlets. The software, when the desired
drainage coefficient is entered and type of surface to subsurface inlet,
will then run a separate routine that will size the surface and
subsurface inlet and the main according to the volume of water entering
through the surface to subsurface inlet, the specified drainage
coefficient, the slope of tile main, and additional laterals and mains
attached to the main for which the surface to subsurface inlet is
draining. The benefit of this method is that surface to subsurface inlets
are placed at the optimum location in the field and the inlet and main
are sized so as to remove the water to a provided specification. This
reduces the probability of continued crop loss due to poor placement of a
surface to subsurface inlet. It also ensures that a main is large enough
to remove water at the desired rate but not too large as to have excess
capacity and thus extra cost of material. All of the above can be done by
hand calculation, but it requires a considerable amount of time and the
novel process described within this invention reduces the time required
significantly.

[0063] Upon completion of placing and sizing of surface to subsurface
inlets, a routine within the program can be initiated with an input
device such as a mouse or keyboard that generates a machine code for
installation as described by U.S. Pat. Nos. 8,155,935 and 7,315,800.

Description and Method of Point 4 (Sizing of Subsurface Laterals and
Mains):

[0064] Both laterals and mains collect water either through the soil or
through other tile mains and laterals. Water collected within the lateral
and main will move at a rate determined by the slope and inside surface
of the lateral and main. The rate water enters a tile lateral and main
will slow down once a threshold of water within the lateral or main is
reached; this can be determined by the Manning's Equation. As such, for
water to enter at the same rate the lateral or main must be increased in
its diameter size. The rate at which water is removed from a subsurface
drainage tile is known as the drainage coefficient, which is usually
measured as number of acre inches of water removed in a day. The drainage
coefficient of a tile lateral is determined by the length of the tile
lateral, its inside surface, its slope, its diameter, and if it has any
surface to subsurface inlets tied into it or any other tile laterals tied
into it. The drainage coefficient of a tile main is determined by its
length, its inside surface, its slope, its diameter, and the number of
surface to subsurface inlets, tile laterals, and tile mains tied into it.
Of note, other aspects of fluid dynamics (e.g., head pressure,
turbulence, etc.) affect the rate and amount of water in a tile lateral
and main as well and may be incorporated into the calculation.

[0065] In the past, tile lateral and main sizes have been determined by
hand calculation or by reliance on local custom. The present invention on
completion of a design as described in point 1 a routine within the
software initiated by an input device such as a keyboard or mouse
determines the required diameter sizes and inside surface of tile
laterals and mains according to a specified calculation. To do so, names
are automatically assigned by the software upon completion of the design
to all tile laterals and mains. A main is then selected by its sequence
number within the software using an input device such as a mouse or
keyboard. Upon selection, a drainage coefficient for the main is
specified and then a computer routine is operated that will identify the
mains length, slope, and number of laterals, mains, and surface to
subsurface inlets connected to it. The routine will then calculate the
required size of the main and inside surface to meet the specified
drainage coefficient with the conditions of length, perforation, slope,
and number of laterals, mains, and attachments to the main. It will also
calculate the required size and inside surface of laterals attached to
the main based on the drainage coefficient entered in for the main. The
routine will then modify the design so as to incorporate the changes of
tile size and inside surface into the information provided for the bid
sheet, map printing, and installation commands for the tile machine as
described by U.S. Pat. Nos. 8,155,935 and 7,315,800. The process is then
run for all of the mains included in the design.

[0066] The benefits of this process are that mains can be quickly sized to
the desired drainage coefficient and inside surface without risk of over
sizing mains and laterals or under sizing mains and laterals. Oversized
mains and laterals have excess capacity that causes the price of material
to be greater than is necessary. Undersized mains and laterals are
incapable of moving the desired amount of water in a set period of time
and thus cause a system to be inefficient. In the past, sizing of
laterals and mains has been very time consuming, so much to the point
that often sizing is not done.

Description and Method of Point 5 (Calibration of Irrigation Inlets):

[0067] When control weirs and irrigation inlets are incorporated in a
subsurface drainage system, it is called a subirrigation system.
Subirrigation systems, which have been used for over half a century,
utilize a subsurface tile system for both drainage and irrigation.
Generally, the control weirs are opened during rainy periods such as
spring and fall and then closed for the summer, drier months. When
closed, irrigation water is added through an inlet in order to fill the
subsurface tile drainage system. The water will be kept within the system
by the control weirs, and the water will flow out of the tile laterals
through the perforations into the soil. The irrigation water will then
raise the water table to that of the roots of field crops where it will
then be absorbed by the field crops. The height required of the water
table depends on soil type and type of crops planted. Height is adjusted
according to placement of control weirs (see point 2).

[0068] In the past subirrigation systems have always been designed by
hand, and often they have been designed on fields with naturally little
to no slope or have been land leveled. Control weirs have been placed by
hand calculation and, like controlled drainage systems discussed in point
2, the number of weirs has been few, often one per main. Irrigation water
has been added at the top of the system and is added constantly until
water flows over the control weir. That is, the water table becomes so
high that it exceeds the level of the vertical pipe or gate of the
control weir and the added irrigation water will flow out of the system
into an outlet.

[0069] The present invention allows for the accurate measurement of the
amount of irrigation water to be added for the whole system and at each
irrigation inlet. Unlike past systems, the present method of application
occurs by having irrigation inlets at every control weirs along a main,
thus allowing each elevation and acreage zone to receive water at the
same time as every other control weir. Of note, irrigation may occur all
at once or in iteration; irrigation can happen in stages where some zones
receive water on the first day, others the second, etc. Any combination
of irrigation timing can be set up. With a completed design and with
placement of control weirs as described in point 2, acreage sizes of each
zone are determined by the activation of a computer routine within the
software using an input device such as a mouse or keyboard. After
specifying the rate and amount of water to be added to the system, a
routine is run that calculates the volume of water to be supplied to each
irrigation zone so as to apply water uniformly to the system at the rate
and total amount desired. The routine will then provide the appropriate
size of irrigation pressure line required for each irrigation inlet and
the total gallons per minute required by the irrigation pump. This
information is then made available in the design.

[0070] Upon completion, a routine within the program can be initiated with
an input device such as a mouse or keyboard that generates a machine code
for installation as described by U.S. Pat. Nos. 8,155,935 and 7,315,800.
A separate routine is then activated within the software using an input
device such as a mouse or keyboard that produces a printed map and
computer that can be provided for installation of the irrigation pump and
irrigation inlets.

[0071] The benefit of this improvement is that exact information on
irrigation quantities to a subirrigation system are made apparent as well
as the size of pressure line and pump required for irrigation. Irrigation
made uniformly to a field through a subirrigation system allows for water
to be applied in short bursts, facilitating deep root growth of field
crops. In addition, water soluble nutrients can be applied with water in
a uniform fashion. A substantial amount of time is also saved in
determining sizes of irrigation inlets, irrigation pressure line, and
pump size.

[0072] The foregoing description of the preferred embodiment of the
invention has been presented for purposes of illustration and
description. It is not intended to be exhaustive or to limit the
invention to the precise form disclosed, and modifications and variations
are possible in light of the above teachings or may be acquired from
practice of the invention. The embodiment was chosen and described in
order to explain the principles of the invention and its practical
application to enable one skilled in the art to utilize the invention in
various embodiments as are suited to the particular use contemplated. It
is intended that the scope of the invention be defined by the claims
appended hereto, and their equivalents. The entirety of each of the
aforementioned documents is incorporated by reference herein.